Counterbalance for overhead doors



' March 16, 1943. "s, w. PARSONS 2,314,015

GOUNTERBALANGE FOR OVERHEAD DOORS Filed Feb. 26, 1941 s Sheets-Sheet 1 'March 16, 1943. s; w. PARSONS I COUNTERBAL ANCH'F'OR OVERHEAD DOORS Fil ed Feb. 26, 1941 l5 Sheets-$heet 2 March 16, 1943. s. w. PARSONS I COUNTERBALANCE FOR- OVERHEAD DOORS 3 Sheets-Sheet 3 Filed Feb. 26, 1941 Patented Mar. 16, 1943 COUNTERBALANCE FOR OVERHEAD DOORS Stuart Parsons, New Britain,- Conn, assignor to The Stanley Works, New Britain, Conn., a corporation .of. Connecticut Application February 26, 1941, Serial No. 380,624

3 Claims.

The present invention pertains to a novel counterbalancing mechanism for an.overhead door of the type having a series of sections hinged to one another and movable first along a vertical section of track and then onto a horizontal section of track as the door opens.

The principal object of the invention is to provide a counterbalancing mechanism including a horizontally disposed coil spring which is torsionally tensioned and untensioned to counterbalance the door as the door moves between open and closed positions, said mechanism includuing means for shifting one of the anchors forv the Spring laterally so that detrimental axial tension and compression is not set up in the spring with resultant buckling and cramping of the spring.

A further object is to provide a counterbalancing mechanism that is particularly durable in use and which renders the action of the door unusually smooth and effortless.

A still further object is to provide a mechanism which counterbalancesthe door easily and accurately and which is not liable to get out of adjustment in service.

Still another object is to provide a mechanism which may be manufactured, assembled and installed as a single unit and at a minimum of cost and effort.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination ofelements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the accompanying drawings:

Figure 1 is a plan view of an articulated door properly mounted in a doorway and counterbalanced by a mechanism made in accordance with the present invention;

Fig. 2 is an enlarged crosssectional view taken through the axis of the counterbalancing mechanism; v

Fig. 3 is a cross-sectionalview taken through line 33 of Fig. 2; and

Fig. 4 shows a portion of the counterbalancing mechanism when the door is in the open position.

The drawings generally indicate a portion of a garage building ID in which there is operably mounted an articulated closure member or door It. The door is opened by moving the same from the vertical position illustrated in Figure l to a 55 horizontal overhead position within the garage. In order to support the door and guide the same between its open and closed positions there is provided a track it having a vertical portion I8 and a horizontal portion connected thereto by a curved or fillet portion 20. As is customary in articulated door assemblies of this type, similar tracks are positioned and secured at each side of the door opening and the tracks operably engage rollers 22 mounted on the door 14. As illustrated in Fig. 3 the curved portion of each track is secured to the doorway by a mounting bracket 24.

Secured to each bracket 24 is a bearing mounting plate 26 for operably supporting a shaft 38 of the counterbalancing mechanism. The bearing mounting plates 26 are disposed at right angles to the door and in parallel relation with each other and are provided with aligned openings 2B in which are located ball bearing'races for rotatably supporting the shaft 38. Inasmuch as the bearing plates 2t and the counterbalancing mechanism adjacent each end of theshaft are similar, a description of one side will serve to explain the construction at both.

The ball bearings 32 of the race are operably secured by an outer race member 34, flanged to the mounting plate as at 36, and by an inner race member 31, press fitted to the hollow shaft 38. The shaft extends laterally to either side of the door and carries like pulleys 40 on the ends thereof. A cylindrical ring. or sleeve 42 fits over the inner race member 37 and the end 43 thereof secures the ball bearingswithin the race-way formed by the members 36 and 31.

The hub 44 of the pulley 40 abuts and properly positions the cylindrical ring 42, and is itself securedin position by a radially disposed set screw 46 which also secures and properly positions the inner race member 31 on the shaft 38. The pulley further includes a substantially V- shaped periphery 48 having on its outer surface a spirally developed groove 50 adapted to properly wind and unwind the door supporting cord or cable 52 without allowing the latter to overrun itself. The lower end of the cable is attached to the adjacent lower corner of the door as by a suitable bracket 54 and to the pulley at a point in the convolution El farthest from the door.

Intermediate of its ends the shaft 38 is surrounded by a coil spring 56 which is adapted to be wound up as the door is closed and to thereby store up energy which aids in opening the door as the spring subsequently unwinds. One end of the spring 56 is rigidly secured (as by a snug fitting) to a two-part sleeve 58 which is itself secured to the shaft as by the set screw 60. The other end of the coil spring is threaded on a collar 62 as at 64. The collar is loosely mounted on the shaft 38 and has a flange 66 formed on its free end wherein there are cut a pair of diametrically opposed holes 68. The walls 69 of the holes 68 taper outwardly from the center substantially as the walls of an hour glass so that the posts located therein permit free sliding movement of the collar, and, as a result, when the collar is crimped out of alignment it does not bind thereon. The posts Til parallel the main shaft 35 and are secured as by riveted ends H to a ring 12 which is itself secured concentrically with the shaft to the mounting plate 26 as by the bolts 14. The sliding fit of the flange holes 68 with the studs 10 permits axial lengthening and contracting of the spring as it is torsionally tensioned and untensioned, thereby eliminating buckling or crimping of the spring.

Briefly, the operation of the counter-balancing mechanism is as follows: Assuming the door is in the closed position illustrated in Fig. 1, the spring is substantially tensioned and subsequently is extended its full length so that the flange 66 is located adjacent the ring 12. However, as the door is opened the torsional tension stored in the spring aids in lifting the door, and, at the same time, the axial length of the spring decreases so as to move the anchor 66 to the position illustrated in Fig. 4. Inasmuch as the tendency of the spring to decrease or increase in length is not obstructed as the door is opened and closed, no axial tension is set up in the spring. It will be observed that a cotter pin 16 is located in the free end of one of the studs 10 in order that the flange collar will not be relieved of the non-rotational restraint imposed by the studs, and thus the spring is always properly torsionally tensioned.

Furthermore, since the present invention eliminates the axial force in the spring, there is little or no tendency of spring failure. In installing the present counterbalance, since the entire mechanism, including the shaft 38, the pulleys 40 and the studs 10 are operably mounted on the two plates, there are no difficult adjustments to be made, and the mechanism may be easily installed and with a minimum of effort and mechanical skill.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim as my invention:

1. A counterbalancing mechanism for an articulated overhead door including a horizontally disposed coil spring which is torsionally tensioned and untensioned to counterbalance the door as the door moves between open and closed positions, a shaft located within said spring and rotatably supported by a pair of spaced supports secured to the doorway frame, means securing one end of the spring to the shaft for rotation therewith, an anchor secured to the other end of the spring and movable lengthwise of the shaft, a post carried by one of said supports parallel with the direction of movement of said anchor, said post engaging and restraining the anchor and the end of the spring carried thereby against rotation and permitting said anchor transverse movement axially relative to said posts so as to allow for elongation and contraction of said spring upon the tensioning and untensioning thereof.

2. A counterbalancing mechanism for an articulated overhead door including a horizontally disposed coil spring which is torsionally tensioned and untensioned to counterbalance the door as the door moves between open and closed positions, a shaft located within said spring and rotatably supported by a pair of spaced supports secured to the doorway frame, means securing one end of the spring to the shaft for rotation therewith, an anchor secured to the other end of the spring and movable lengthwise of the shaft, a pair of posts carried by one of said supports in parallel with each other and with the direction of movement of said anchor, said anchor being provided with diametrically opposed holes having outwardly divergent conical walls for receiving and engaging said posts, the engagement of said walls with said posts restraining the anchor and the end of the spring carried thereby against rotation and permitting said anchor transverse movement axially relative to said posts so as to allow for elongation and contraction of said spring upon the tensioning and untensioning thereof.

3. A counterbalancing mechanism for an articulated overhead door including a horizontally disposed coil spring which is torsionally tensioned and untensioned to counterbalance the door as the door moves between open and closed positions, a shaft located within said spring and rotatably supported by a pair of spaced supports, a pair of brackets secured to the doorway frame, each bracket carrying one of said supports and a track in which the door is operably guided, means securing one end of the spring to the shaft for rotation therewith, an anchor secured to the other end of the spring and movable lengthwise of the shaft, a pair of posts carried by one of said supports in parallel with each other and with the direction of movement of said anchor, said anchor being provided with diametrically opposed holes having outwardly divergent conical walls for receiving and engaging said posts, the engagement of said walls with said posts restraining the anchor and the end of the spring carried thereby against rotation and permitting said anchor transverse movement axially relative to said postsso as to allow for elongation and contraction of said spring upon the tensioning and untensioning thereof.

STUART W. PARSONS. 

